Call of duty 5
perfect dark zero
rainbow six vegas 1/2
Ghost recon 2 (only terrorist hunt for coop)
Guitar hero world tour

That's all I know of from my games. I think that out of that list, perfect dark would have the best cooperative.

Resident evil 5 is coming out next month I believe and the demo has some fantastic splitscreen cooperative. If you havnt tried it already you should.

Cod4 and cod:waw come to mind... but thats only recent.

I do find the donkey kong 64 mine cart ride very memorable.

I had a problem too like that. My CC expired and i didnt pay the bill for 2 months my fault. My account got suspended i called xbox and they told me the problem, i gavbe him my new CC number he put it in and it worked like a charm. I was on live in about 10 minutsscphan